<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <title>新增长度单位</title>
  <style>
    * {
      margin: 0;
      padding: 0;
    }
    .box1{
      width: 200px;
      height: 200px;
      background-color: skyblue;
      padding: 5px;
      border: 5px black solid;
      margin-bottom: 20px;
      resize: horizontal;
      overflow: hidden;
    }
  </style>
</head>
<body>
  <div class="box1"></div>
  
</body>
</html>